Apparatus for the production of continuous electrical oscillations.



H. MANDBRS.

APPARATUS FOR THE PRODUCTION OF CONTINUOUS ELECTRICAL OSUILLATIONS.

APPLICATION FILED 00T.30,1909.

1,1 05,984. Patented Aug/1, 1914.

mwmto'c Wvtmeooco UNITED STATES PATENT oFFIoE.

HORACE MANDERS, OF LONDON, ENGLAND.

APPARATUS FOR THE PRODUCTION OI CONTINUOUS ELECTRICAL OSCILLATIONS.

To all whom it may concern.

Be it known that I, HORACE MANDERS, a subject of the King of Great Britain, of London, England, have invented certain new and useful Improvements in Apparatus for the Production of Continuous Electrical Oscillations, of which the following is a specification.

This invention relates to improvements in and relating to apparatus for the produc tion of continuous electrical oscillations, and to the application of the same.

I have previously (in the specification of British Patent No. 5164 A. D. 1907) described a method and means of producing oscillatory currents of electricity from continuous currents of the same, In which the principal feature is that the cathode of the oscillator is composed of aluminium, or of some metal of relatively low atomic weight; whereas the anode must be composed of a metal of higher atomic weight than that of the cathode.

I have found that in the production of continuous electrical oscillations remarkable results as regards the regularity, continuity and duration of the oscillating arc can be obtained by using a pair of condenser electrodes of a special form, namely, that of a block having a flattened discharge area at and near the axis, whereas the portion outside this area is thrown back or beveled ofl".

The present invention consists in the use of such block electrodes for the production of continuous electrical oscillations.

The invention further consists in the employment of a modified form of such block condenser electrodes, wherein the flat central discharge portion is raised as a nipple above a rounded mammary shaped base.

The invention further consists in the application t0 the chamfered or thrown back faces of such block condenser electrodes of insulating material for the purpose of increasing the dielectric effect between the chamfered or thrown back parts of the pair of block electrodes.

In the accompanying drawings: Figure 1 represents in plan and elevation a form of my block electrode. Fig. 2 is an elevation showing the application of insulation to the beveled oil portion. Fig. 3 is a view of a pair of electrodes with insulation similarly applied. Fig. 4 is an elevation of a modified form of the block electrode in which the I Specification of Letters Patent.

Application filed October 30, 1909.

Patented Aug. 4, 1914.

Serial No. 525,451.

peripheral non-discharge portion is thrown back in a more pronounced way from the central portion, giving a block electrode of mammary form. Fig. 5 illustrates an electrode like that shown in Fig. l, with a dielectric applied to the thrown back portion. Fig. 6 illustrates the electrodes applied to a closed interrupter.

I prefer to make the block electrodes from metal rod of large diameter, but, as rod of larger diameter than 1 inch is generally unobtainable, for larger sizes special castings may be made. Ordinarily, I cut ed a length of an inch and a half, more or less, from r d of one inch, more or less, in diameter; in the center of one end I sink a female screw to take a conducting rod, which also serves as a support to the electrode. The opposite end of this block is turned or filed and emery papered until it is quite smooth and plane. Then, from the center, I draw a circle, the rim of which is about an eighth of an inch, more or less, from the circumference of the block (A, Fig. 1). The part contained within the said circle is the surface or area of discharge; the part which lies outside, between the circle and the circumference of the block, I bevel off, or chamfer, (B, Fig. 1). When completed, these electrodes present the appearance of a flattened hemisphere surmounting a cylinder. W'hen the circular, flat, plane surfaces of two such electrodes are placed opposite to one another so as to articulate and form an arc-gap, and the circuit is closed, an oscillatory condenser discharge takes place be tween them. The remainder of the opposing surfaces of conductingmaterial,beingchamfered and so thrown back from each other, offer a greater thickness of dielectric between the two armatures; hence, the discharge is confined to the desired area within the inner circle.v When usedwith high voltages, I prefer to strengthen the dielectric by filling up the chamfered area of the armatures with a suitable insulating material C. I find that for voltages up to 200, or a little more, the preparation of kaolin, sold under the name of Fortafix or Cement-ium is very eflicient for the purpose; but for higher voltages, I find it best to use either steatitc, papier-mache, ordinary court plaster, or superimposed layers of thin. silk. These layers of silk are so disposed that the central oles gradually increase in diame-' ter as each recedes from. the discharge area;

so that, in section, the insulating material of a single electrode gives th appearance of a centrally hollow plano-concave lens, F 'ig. 2, and when two such electrodes are placed'opposite to each other in the arc-gap, the appearance of the inter-articulating insulatin substance is that of a centrally hollow bl concave lens, Fig. 3.

Anothe plan of making these electrodes, which accomplishes the same purpose, is to cut away a portion D of the circumference of the block, after leveling as before, about an eighth of an inch, or more, toward the center, according to the diameter of-the block,and at least a sixteenth of an inch, or more, in; depth the edge of theelevated circle is slightly chamfered, but the shoulder is chamfered as alreadvdescribed, until the blockpresents a breast and nipple or mammary appearance, Fig. 4. -The chamfered shoulder may be treated with appropriate insulating material (Fig. 5) as already described, but not necessarily to the level of the summit of the nipple.-

These condenser-electrodes may be used in the arc-gap as pairs' of,a-.similar kind; or one of the air may be of the flattened hemispherical kind first described, and the oltlher, of the same pair, of the mammary s ape.

-The.electrodes are. shown atze' and 6, Fig. 6,2 applied to a' known type-of inter-- rupten- 1 I have also discovered that when the condenserelectrodes, above described, are used, there are certain exceptions to the general rule of the electrical functional relations of anode and cathode promulgated in my British Patent No. 5164 A. "D. 1907. I have ascertained that, with my condenser electrodes as above, I can obtain excellent oscillations when aluminium is opposed to aluminium; also iron to iron; and zinc to zinc (especially in. the latter case when the anode is of the mammary form), that when iron and zinc are 0 posed to each other within the arcgap tie oscillations are equally good which ever metal is used as anode or cathode, re-

spectively, to the other. Henceany of these four-combinations of metals may be used to obtain continuously -maintai-ned electrical oscillations from an ordinary alternating current- I have also ascertained that, with my condenser block electrodes, as above, when iron, especially in the form of steel, as anode, is opposed to cadmium as cathode, excellent oscillations are obtained, which are best when the discharging surface .of the anode electrode is of less area (as in the mammary form) than that of the cathode; that when cobalt as anode is opposed to zinc as cathode, very powerful and steady oscillations are roduced, more especially when the anode 1s of the mammary form.

I have ascertained that many advantages result when the oscillating arc discharge is caused to take place in compressed air or in an atmosphere of nitrogen or carbon dioxid, especially when such. atmosphere is under a pressure of one or more atmospheres, and I have found that the results are-particularly advantageous when the contained air or gas'is keptdry in the chamber and the products of combustion are absorbed by soda lime or the like. Fig. 6 re resents a suitable apparatus for attaining 1; 1e pur- I pose. Such apparatus comprises an arc gap chamber a which may consist of a glass vessel b the rim of which fits into a groove 0 in the under'surface of a lid 03 made of an insulatin material, such as vulcanite. 6 6 are the b ock electrodes attached to rods f g of conducting material, the former of which passes down through a stufiing box It on the lid: and can be adjusted by aumicrometer screw i. i is the terminal attached to the bent rod 9 of the lower electrode and 3' is the other terminal, in flexible connection by a wire is with the rod f. l is a valve for admitting the air or gas to the chamber a, and

m represents a manometer for indicatingthe pressures in the chamber. 11. is a stop cock for allowing-the air or gas to. escape. o is a base board to which the lid is clamped by rods .p and butterfly nuts 1 so that the chamber becomes hermetically sealed. when the parts are clamped together, the groove 0 being lined with rubber or elastic material with this object. Any other suitable means ma be employed to provide for hermetic sea ing of the chamber.

I may construct the body of the arc gap chamber of metal. In this case the rod for carrying the lower electrode may project up from the center of the bottom of the chamber. If desired the conducting rods that carry the electrodes may be disposed horizontally. Soda lime or like absorbent material may be placed in the chamber for the purpose above mentioned.

lVhat I claim and desire to tors-Patent is 1. In apparatus for the production of continuous electrical oscillations, a pair of electrodes of block form, each havinga flattened discharge area at and near the: axis, and having the portion outside-this area at the discharge side thrown back, substantially as described.

. 2. In apparatus for the production of continuous electrical oscillations, an electrode of block form having a flattened discharge area at and-pear-the axis and havin the portion outside this area at the discharge side thrown back and having an insulating material applied to said thrown back portlOII. f

3. In apparatus for the production of continuous; e ectrical oscillations, apair of electrodes of block form, each having a flattened discharge area at and near the axis and having the portion outside this area at the discharge side thrown back, the anode of said pair consisting of iron and the cathode of cadmium.

4. In apparatus for the production of continuous electrical oscillations, a pair of electrodes of block form each having a flattened discharge area at and near the axis and having the portion outside this area at the discharge side thrown back, in combination with insulating material applied in between the said thrown back portion.

5. In apparatus for the production of con tinuous electrical oscillations, a pair of electrodes of block form, each having a flattened discharge area at and near the axis and having the portion outside this area at the discharge side thrown back, the flattened discharge area being upon a nipple-like portion projecting from the body of the block, substantially as described.

6. In apparatus for the production of continuous electrical oscillations, a pair of electrodes of block form, each having a flattened discharge area at and near the axis and having the portion outside this area at the dlscharge side thrown back, the flattened discharge area being upon a nipplelike portion projecting from the body of the block in combination with insulating material applied between the thrown back portions of the electrodes, substantially as described.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

HORACE MANDERS.

WVitnesses:

HENRY ALLEN RYER, ROBERT MILTON SPEARPOINT. 

